diff --git a/ci_prereq.sh b/ci_prereq.sh
index 1f8625b..25f82b8 100755
--- a/ci_prereq.sh
+++ b/ci_prereq.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 
+sudo apt update
 sudo apt install -y \
   devscripts \
   equivs
diff --git a/src/command.c b/src/command.c
index 864d7a3..4142419 100644
--- a/src/command.c
+++ b/src/command.c
@@ -50,6 +50,9 @@
  */
 
 #include <dos.h>
+#ifndef _A_DEVICE
+#define _A_DEVICE 0x40u
+#endif
 #include <libc/dosio.h>
 #include <io.h>
 #include <libc/getdinfo.h>
@@ -2693,7 +2696,8 @@ static void perform_dir(const char *arg)
       }
     if (first)
       {
-      if ((ffrc = findfirst_f(full_filespec, &ff, attrib, &ffhandle)) != 0)
+      if (((ffrc = findfirst_f(full_filespec, &ff, attrib, &ffhandle)) != 0) ||
+          ff.ff_attrib == _A_DEVICE )
         {
         puts("File not found");  // informational message -- not an error
         return;